FA versus A 645 lenses

As the release date of the 654D is approaching and the availability on the used market of FA lenses let's just say is not abundant, I would like to know from members that have had experience with both FA and A version of a lens or zoom, if in fact there is a significant difference in the optical quality of one versus the other.

I haven't had that much practical experience with my 645 gear, but I can say that the A 120mm macro made a much better impression on me than the FA version. Obviously many of the lenses share the same optics, and while the key difference between A and FA lenses is obviously the autofocus, the important question is how truly beneficial is AF when you're already out there carrying a tripod an twenty pounds of gear

I consider the 645 120 macro one of the best that Pentax has ever made, easily rivaling the FA & A200 F4 macro (35mm). Despite the A & FA versions being optically the same, the FA has focus precision issues with it's mechanism. The A has a more robust & firmer focus action & is less likely to shift under critical focusing.

I haven't had that much practical experience with my 645 gear, but I can say that the A 120mm macro made a much better impression on me than the FA version. Obviously many of the lenses share the same optics, and while the key difference between A and FA lenses is obviously the autofocus, the important question is how truly beneficial is AF when you're already out there carrying a tripod an twenty pounds of gear

Haven't used mine for a while through lack of opportunity. Here is an old one shot with a Ds. Rushed processing could have been better. Looks a little too magenta/red but was shot very late in the afternoon in warm sunshine.

Originally posted by Adam

Perhaps it's worth a try on the K-7, then! I haven't gone down that road yet (although the A/FA 200 macros did a good job)

I consider the 645 120 macro one of the best that Pentax has ever made, easily rivaling the FA & A200 F4 macro (35mm). Despite the A & FA versions being optically the same, the FA has focus precision issues with it's mechanism. The A has a more robust & firmer focus action & is less likely to shift under critical focusing.

I will take your word for it as I just purchased one on eBay (from Canada cut the brokerage and shipping cost) for $175
It looks used and according to the description has some traces of oil on the blades that does not affect operation.
It might have to go to Eric at some time.
Has anybody sent lenses to Eric for TLC? I have only sent cameras.

I just purchased the FA 2.8/150 and FA 4/200 locally, for £470 I could not resist. Especially since they apparently were never used: not just in their original boxes with hoods and cases, and plastic etc down to the little bags to avoid humidity, but so pristine that they may have come from a collector.

Got the feeling I might have bargained even harder. My first FA lenses for the 645, and I was surprised by their smoothness of operation. No time yet to test their IQ. Read about the difficulty of keeping the hood and lens in bag but the hoods can be reversed over the lens, so they easily fit into any bag.

Only thing is, that I may have to part from the 3.5/150 now, it's a bit overkill. Can't hold on to it just in case the FA version develops a problem.